The feasibility of property enhancement of heavily filled dental composite systems through modifications of both the filler system and resin matrix will be evaluated. Novel fillers, with a prior history of successful reinforcement in non-dental polymers due to an advantageous aspect ratio, will be employed alone or in conjunction with conventional silica reinforcement fillers at levels of up to 75 w/o. A resin system with a higher degree of conversion and lower viscosity than conventional Bis-GMA/diluent systems will also be examined as a matrix for these novel fillers. Measurement of standard mechanical properties such as diametral tension, compression and hardness, as well as modulus, modulus vs. temperature and glass temperatures will be determined. Successful protypical systems will then be evaluated for adaptation, finishing, marginal leakage, as well as linear thermal expansion and water sorption.